Atlassian JIRA Server and Atlassian JIRA Data Center are both products of Atlassian Australia, Atlassian JIRA Server is a server version of a defect tracking management system. Atlassian JIRA Data Center is the data center version of Atlassian JIRA, which is a security vulnerability that could be exploited by an attacker to determine if a user name is valid through a missing privilege check. whether the username is valid.